The present invention generally relates to the field of honeycomb structures. In particular, the invention relates to removing material from honeycomb structures.
Honeycomb structures are often used in the field of gas turbine engines, for example, as a seal or a filler material. Temperatures inside gas turbine engines can often reach potentially damaging levels. Thus, bleed passages are often used to allow air to flow through the engine. The bleed passages function to either reduce the temperature within the gas turbine engine or to maintain the temperature within the gas turbine engine at an operational level. An example of a bleed passage would be on a forward inner nozzle support having a plurality of apertures. A honeycomb structure positioned on the forward inner nozzle support is commonly provided with bleed holes that are aligned with the apertures of the forward inner nozzle support. Hot air can thus flow from within the gas turbine engine and through the forward inner nozzle support and the honeycomb structure, maintaining the temperature of the gas turbine engine at operational levels.
Due to the harsh environment of gas turbine engines, honeycomb structures positioned within the gas turbine engine occasionally need to be repaired or replaced. For example, when a groove in the honeycomb structure becomes too deep, the original honeycomb structure is removed. One method of repairing honeycomb structures is to then braze a new honeycomb structure onto the surface of the forward inner nozzle support on which the original honeycomb structure was positioned. After the surface of the forward inner nozzle support has been brazed with the new honeycomb material, some of the material must be removed from the honeycomb structure in order to allow hot air to continue to flow through the forward inner nozzle support and the honeycomb structure.
A method that is currently being used to remove material from honeycomb structures is electrode discharge machining (EDM). While EDM is effective in providing holes in the honeycomb structures, it is a timely and costly process. The equipment needed for EDM is expensive, and the process is time intensive. For example, using EDM to provide 90 holes within a circumference of a honeycomb structure can take up to between approximately 8 hours and approximately 9 hours. During the time that the holes are being created within the honeycomb structure, the gas turbine engine is not in use, costing valuable operating time. Thus, it would be beneficial to provide a timely and less costly method of providing holes within a honeycomb structure.